272 Setting the Eccentrics.
red ochre applied to its journals. Being turned round in the
bearings by means of the temporary handles, L, it is lifted away,
the brasses scraped, and the method repeated until a perfect fit is
obtained. The last time the shaft is removed, it is taken to the
marking table to line the eccentric key ways. The angles for each
sheave are shewn at M, being known after design, and are there
called a and ft; x and y are therefore found from a table of natural
sines.
For oc = radius of shaft x sin a, and y = radius of shaft x sin fi.
TABLE OF NATURAL SINES FOR ANGLES UP TO 45°.
D«K-
Sine.
Deg,
Sine.
Deg.
Sine.
Dcg. Sine
~r
•008/2
12
•20791
23i
*39875
35 j "57357
•01745
12*
'21644
24
•40673
35* I -58070
4
•02617
13
•22951
24 1
•41469
36 -58778
I
•03489
13*
•23344
25
•42262
36J
•59482
2*
•04362
H
•24192
25*
"43051
37
•60181
2
•05233
Mi
•25038
26
•43B37
37i
•60876
3*
'06104
J5,
•25882
26*
•44619
38
•61566
3
•06975
'5*
•26724
27
'45399
38i
'62251
4*
'07846
16
•27563
27*
•46175
39
•62932
4
•08715
16*
'28401
28
•46947
39i
•63607
5*
•09584
17
•29237
28*
•47715
40
•64278
5
•*0453
17*
30070
29
'48481
4oi
'64944
6*
•11320
18
30901
29^
•49242
41
•65606
6
•12187
18*
'31730
30
•5OOOO
4^
•66262
7*
•13052
19
32556
30*
•50753
42
•66913
8
"I39I7
19*
•33380
31
"5* 5°3
42|
•67559
8*
-14781
20
'34202
31*
•52249
43 | "68200
9
•15643
20*
•35020
32
•53992
43i
•68835
9*
•16504
21
' 35836
32*
*5373o
44
•69465
10
•17364
21*
•36650
33
•54464
44i
70091
10*
-18223
22
•37460
33*
•55193
45
70710
II
•19081
22*
38268
34
•55919
I 1*
•19936
23
•39073
34*
'56640
The heights x and y above or below centre line have to be scribed
by laying the crank webs vertically or horizontally a$'~at p and w,
and the distance Q also measured, giving the centre line between
the two eccentric rods. Slot-drill the keyways. Then drive the
sheaves upon the shaft, to which they should fit tightly; put in
the keys, and replace the crank in its bearings, (It may be noted